HTML-CSS: Mouse cursor gradient tracking

Last update on May 28 2022 07:25:11 (UTC/GMT +8 hours)

HTML-CSS : Exercise-8 with Solution

Using HTML, CSS, JavaScript create a hover effect where the gradient follows the mouse cursor.

Declare two CSS variables, --x and --y, used to track the position of the mouse on the button.
Declare a CSS variable, --size, used to modify the gradient's dimensions.
Use background: radial-gradient(circle closest-side, pink, transparent); to create the gradient at the correct position.
Use Document.querySelector() and EventTarget.addEventListener() to register a handler for the 'mousemove' event.
Use Element.getBoundingClientRect() and CSSStyleDeclaration.setProperty() to update the values of the --x and --y CSS variables.

HTML Code:

<!--License: https://bit.ly/3GjrtVF-->
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Using HTML, CSS, JavaScript create a hover effect where the gradient follows the mouse cursor</title>
</head>
<body>
<strong>Preview:</strong><br>
<button class="mouse-cursor-gradient-tracking">
  <span>Hover me</span></button>
</body>
</html>

CSS Code:

<style>

.mouse-cursor-gradient-tracking {
  position: relative;
  background: #7983ff;
  padding: 0.5rem 1rem;
  font-size: 1.2rem;
  border: none;
  color: white;
  cursor: pointer;
  outline: none;
  overflow: hidden;
}

.mouse-cursor-gradient-tracking span {
  position: relative;
}

.mouse-cursor-gradient-tracking:before {
  --size: 0;
  content: '';
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: var(--size);
  height: var(--size);
  background: radial-gradient(circle closest-side, red, transparent);
  transform: translate(-50%, -50%);
  transition: width 0.2s ease, height 0.2s ease;
}

.mouse-cursor-gradient-tracking:hover:before {
  --size: 200px;
}
}

</style>

JavaScript Code:

<script>
let btn = document.querySelector('.mouse-cursor-gradient-tracking');
btn.addEventListener('mousemove', e => {
  let rect = e.target.getBoundingClientRect();
  let x = e.clientX - rect.left;
  let y = e.clientY - rect.top;
  btn.style.setProperty('--x', x + 'px');
  btn.style.setProperty('--y', y + 'px');
});

</script>

HTML-CSS Editor:

See the Pen html-css-practical-exercises by w3resource (@w3resource) on CodePen.

HTML-CSS: Tips of the Day

What is the difference between id and class in CSS, and when should I use them?

Example:

#header_id {font-color:#fff} .header_class {font-color:#000}

(Note that CSS uses the prefix # for IDs and . for Classes.)

However color was an HTML 4.01 <font> tag attribute deprecated in HTML 5. In CSS there is no "font-color", the style is color so the above should read:

Example:

#header_id {color:#fff} .header_class {color:#000}

The text would be white.

Ref: https://bit.ly/39Stv4P